What is fluorosis?

• A. Excess fluoride causes porous enamel with staining and pitting.
• B. Fluoride deficiency leads to brighter enamel.
• C. Fluoride varnish actively removes all bacteria from caries.
• D. Fluoride strengthens enamel by penetrating dentin.

Answer: (A)

Fluorosis is a developmental disturbance of enamel caused by excessive fluoride exposure during the period when enamel is forming. The excess fluoride disrupts ameloblast activity, leading to hypomineralization and porosity in the enamel. That porous enamel becomes visible as staining and can develop pitting in more severe cases. Fluoride normally helps strengthen enamel by promoting remineralization, but fluorosis reflects overexposure, not a strengthening effect. The other statements don’t fit: fluoride deficiency isn’t associated with “brighter” enamel, fluoride varnish does not remove all bacteria, and fluorosis involves enamel formation rather than dentin or a process that penetrates dentin to strengthen it.